yocto-bsp/genericarm64: add virtio-gpu

testimage on core-image-sato fails in parselogs and xorg tests.  We can
add the virtio gpu to address these issues (like what is being done in
qemuarm, qemuarm64, and qemuarmv5).

(From meta-yocto rev: ddf075e2abfba6479efc2bc5fe1c41ba6079e355)

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto-bsp/conf/machine/genericarm64.conf

@@ -51,6 +51,8 @@ QB_DEFAULT_FSTYPE = "wic"
 QB_FSINFO = "wic:no-kernel-in-fs"
 # Mount the wic rootfs as a virtio block device
 QB_ROOTFS_OPT = "-drive id=root,file=@ROOTFS@,if=none,format=raw -device virtio-blk-pci,drive=root"
+# Virtio graphics
+QB_GRAPHICS = "-device virtio-gpu-pci"
 # Virtio serial consoles
 QB_SERIAL_OPT = "-device virtio-serial-pci -chardev null,id=virtcon -device virtconsole,chardev=virtcon"
 QB_TCPSERIAL_OPT = "-device virtio-serial-pci -chardev socket,id=virtcon,port=@PORT@,host=127.0.0.1,nodelay=on -device virtconsole,chardev=virtcon"